STYLE: add usage notes to more utilities and solvers

applications/solvers/discreteMethods/molecularDynamics/mdEquilibrationFoam/mdEquilibrationFoam.C

@@ -37,6 +37,11 @@ Description
 
 int main(int argc, char *argv[])
 {
+    argList::addNote
+    (
+        "Equilibrate and/or precondition molecular dynamics systems."
+    );
+
     #include "addCheckCaseOptions.H"
     #include "setRootCase.H"
     #include "createTime.H"

applications/solvers/discreteMethods/molecularDynamics/mdFoam/mdFoam.C

@@ -39,6 +39,11 @@ Description
 
 int main(int argc, char *argv[])
 {
+    argList::addNote
+    (
+        "Molecular dynamics solver for fluid dynamics."
+    );
+
     #define NO_CONTROL
     #include "postProcess.H"